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From:   Alex Shi <alex.shi@linux.alibaba.com>
To:     akpm@linux-foundation.org, mgorman@techsingularity.net,
        tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru,
        daniel.m.jordan@oracle.com, willy@infradead.org,
        hannes@cmpxchg.org, lkp@intel.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
        shakeelb@google.com, iamjoonsoo.kim@lge.com,
        richard.weiyang@gmail.com, kirill@shutemov.name,
        alexander.duyck@gmail.com, rong.a.chen@intel.com, mhocko@suse.com,
        vdavydov.dev@gmail.com, shy828301@gmail.com, aaron.lwe@gmail.com
Cc:     Michal Hocko <mhocko@kernel.org>
Subject: [PATCH v19 09/20] mm/memcg: add debug checking in lock_page_memcg
Date:   Thu, 24 Sep 2020 11:28:24 +0800
Message-Id: <1600918115-22007-10-git-send-email-alex.shi@linux.alibaba.com>
In-Reply-To: <1600918115-22007-1-git-send-email-alex.shi@linux.alibaba.com>
References: <1600918115-22007-1-git-send-email-alex.shi@linux.alibaba.com>
Precedence: bulk

Add a debug checking in lock_page_memcg, then we could get alarm
if anything wrong here.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/memcontrol.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 368e6ac644f0..6acc6a60c52b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2097,6 +2097,12 @@ struct mem_cgroup *lock_page_memcg(struct page *page)
 	if (unlikely(!memcg))
 		return NULL;
 
+#ifdef CONFIG_PROVE_LOCKING
+	local_irq_save(flags);
+	might_lock(&memcg->move_lock);
+	local_irq_restore(flags);
+#endif
+
 	if (atomic_read(&memcg->moving_account) <= 0)
 		return memcg;
 
-- 
1.8.3.1